BIOLOGY1010

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A true-breeding plant that produces yellow seeds is crossed with a true-breeding plant that produces green seeds. The seeds of all of the offspring are yellow. Why?

The yellow allele is dominant to the green allele

The parents of a child with unusual disease symptoms take the child to a doctor for help. The doctor suspects that the condition might have a genetic basis. She recommends that the child be taken to a specialty clinic where physicians and staff members are trained to diagnose genetic diseases and counsel parents. Ultimately, the child is diagnosed with a rare recessively inherited disease. The parents are tested for the gene, and both are found to be heterozygous. The parents want to have another child but are afraid this child will also be affected.

1/4

A true-breeding plant that produces yellow seeds is crossed with a true-breeding plant that produces green seeds. The F1 plants have yellow seeds. What is the expected phenotypic ratio of seed color of the offspring of an F1 × F1 cross?

3:1

Attached earlobes are recessive to free earlobes. What genotypic ratio is expected when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

1:1

Attached earlobes are recessive to free earlobes. What is the probability of having a child with attached earlobes when an individual with attached earlobes mates with an individual heterozygous for free earlobes?

50%

An individual who is homozygous ______.

carries two copies of the same allele for a gene

Which of these crosses will only produce heterozygous offspring?

AA x aa

To determine the phenotype of an individual who expresses a dominant trait, you would cross that individual with an individual who ______.

is homozygous recessive for that trait

A couple has two female children. What is the probability that their next child will be male?

50%

An individual heterozygous for cystic fibrosis ______.

is a carrier

Achondroplasia is a form of dwarfism caused by a dominant allele. The homozygous dominant genotype causes death, so individuals who have this condition are all heterozygotes. If a person with achondroplasia mates with a person who does not have achondroplasia, what percentage of their children would be expected to have achondroplasia?

50%

What is the key to the recognition of incomplete dominance?

The phenotype of the heterozygote falls between the phenotypes of the homozygotes.

An individual with (naturally) curly hair and an individual with (naturally) straight hair mate; all of their offspring have (naturally) wavy hair. If an individual with wavy hair mates with an individual with straight hair, what is the probability that their child will have curly hair?

0%

Marfan syndrome is the result of inheriting a single allele. Individuals with Marfan syndrome are tall and long-limbed, and have both cardiovascular and eye defects. The inheritance of Marfan syndrome is an example of ______.

pleiotropy

In humans, the inheritance of ______ is best explained as being polygenic.

height

In the accompanying art you see a table with the actual number of offspring that resulted from a dihybrid cross. The numbers do not show the 9:3:3:1 ratio predicted. One phenotype occurred more than predicted; another occurred less. The reason could be because ______.

some of the alleles were linked

Recombinant offspring were produced by the mating shown in the accompanying art. What is the recombination frequency of purple round and red long offspring?

11%

Assume that having three nostrils is inherited as a sex-linked trait on the Y chromosome. A man with three nostrils has a daughter who has a son with a man who has only two nostrils. What is the probability that the three-nostriled man's grandson has three nostrils?

0%

Red-green color blindness is inherited as a sex-linked recessive trait. The gene is found on the X chromosome. How can a man with normal color vision father a daughter who is red-green color-blind?

He can't (unless there is a mutation).

At one point, you were just an undifferentiated, single cell. You are now made of many cells; some of these cells function as liver cells, some as muscle cells, some as red blood cells, while others play different roles. What name is given to the process that is responsible for this?

cellular differentiation

Consider the following figure, which outlines cloning by nuclear transplantation. Why does the clone not resemble the surrogate mother?

The clone would exhibit characteristics of the genetic donor, not the surrogate.

To make a clone - a genetically identical organism - from a mammalian cell, the cell must ______.

be dedifferentiated

Possible uses of reproductive cloning include ______.

the production of potentially valuable drugs the production of genetically identical animals for experimentationthe production of organs in pigs for transplant into humansrestocking populations of endangered animals-------all of the above.